Colorimetric detection of thiol-containing amino acids using gold nanoparticles

This paper reports findings of an investigation of the unusual colorimetric change of gold nanoparticles in the presence of thiol-containing amino acids such as homocysteine, cysteine and glutathione. The colorimetric change for homocysteine exhibits a rate that is about two orders of magnitude high...

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Bibliographic Details
Published in:Analyst (London) 2002-04, Vol.127 (4), p.462-465
Main Authors: ZHANG, Felicia X, LI HAN, ISRAEL, Lisa B, DARAS, Jason G, MAYE, Mathew M, LY, Nam K, ZHONG, Chuan-Jian
Format: Article
Language:English
Subjects:
Amino Acids - chemistry
Biological and medical sciences
Chemistry
Colloidal state and disperse state
Colorimetry - methods
Disperse state. Micelles
Exact sciences and technology
Fundamental and applied biological sciences. Psychology
General and physical chemistry
Gold
Molecular biophysics
Nanotechnology
Physical and chemical studies. Granulometry. Electrokinetic phenomena
Physico-chemical properties of biomolecules
Sulfhydryl Compounds
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Summary:This paper reports findings of an investigation of the unusual colorimetric change of gold nanoparticles in the presence of thiol-containing amino acids such as homocysteine, cysteine and glutathione. The colorimetric change for homocysteine exhibits a rate that is about two orders of magnitude higher than that for cysteine, and at least five orders of magnitude higher than that for glutathione. The reactivity is effectively reduced or suppressed by the coexistence of either cysteine or glutathione. It is believed that the reactivity involves encapsulation of the particles by the thiol-containing amino acids which is followed by crosslinking at the encapsulating shells. In comparison with cysteine and glutathione, homocysteine has a slower encapsulating rate but a faster crosslinking rate. Implications of the findings of the interfacial encapsulation and crosslinking reactivities of gold nanoparticles to potential nanoparticle-enhanced analytical detection of thiol-containing amino acids are also briefly discussed.
ISSN:0003-2654
1364-5528
DOI:10.1039/b200007e